The present invention concerns a mixing device and a filling machine.
Filling machines of the kind set forth in the opening part of this specification serve for filling pasty foodstuff masses or materials in packagings. Thus such filling machines can be used for filling meat products such as sausage meat which is to be heated in water, ground meat, small sausages or the like into cases of natural or synthetic casing skin. A filling machine has a filling hopper for receiving the material, a conveyor pump and a filling tube for delivery of the material. It is possible to connect downstream of the filling machine for example clippers for clamping off ends of a sausage portion, filling flow dividers for dividing up the flow of material into a plurality of individual flow portions or other so-called accessory devices which can be coupled to a filling machine. A filling machine can also be coupled to a downstream-connected mixing device of the kind set forth in the opening part of this specification.
Mixing devices are used for example when filling sausage meat materials to be heated in water. When filling such sausage meat materials, that can involve agglomeration of air present in the material, that is to say the formation of relatively large air bubbles within the material, which are unwanted and are not accepted by customers. Air contained in the material is finely distributed by means of a mixing device connected downstream of the filling machine. Different kinds of mixing devices are used in the state of the art.
Thus nozzles arranged within a tubular housing and having a reduction in cross-section are used. When the sausage meat material containing the air flows through the nozzle, large air bubbles are reduced in size for example by virtue of turbulence. Depending on the respective kind of product, a special nozzle diameter is used. Installation and conversion and the complication and expenditure linked thereto are considered to be a disadvantage. In addition inclusions contained in the foodstuff material, for example pieces of mushroom in sausage meat, can be damaged or destroyed by virtue of the reduction in cross-section.
In addition, labyrinth nozzles disposed within the housing of the mixing device are used, such nozzles having a plurality of labyrinth-like deflection elements which provide for multiple deflection of the material and thereby provide for an air distribution effect. This can also involve damage to inclusions, for example mushrooms. In addition longer fibers present in the material such as tendons and sinews or the like can remain caught up at the deflection elements, for example the edges thereof, and can accumulate there, which can result in blockage of the labyrinth nozzles.
In addition, static mixers with separating elements, which are similar to the labyrinth nozzles are known, which also provide for deflection of the flow of the material, but they also suffer from the disadvantage that inclusions such as mushrooms are damaged at the separating surfaces or edges of the separating elements or elongate tendons or sinews or fibers remain caught up at the edges and cause blockages.